Ask anyone in Dallas if law enforcement needs to first have a warrant in order to use dogs to try and detect the presence of drugs in a home, and he or she would likely answer yes. He or she would be right, too. The United States Supreme Court has ruled that any investigation of a home and its surroundings meets the definition of a search, and therefore requires a warrant. Yet what if an officer wants to use a dog to search a car for drugs?
The Supreme Court has determined that drivers do not have the expectation of privacy in issues regarding the smelling of their cars. Thus, an officer searching through a car with a drug-sniffing dog does not legally constitute a search, so no warrant is needed.
However, a recent decision by the Supreme Court determined that without probable cause, law enforcement officials cannot prolong a traffic stop in order to conduct a dog sniff search. Even if officers believe they have probable cause due to the reaction of the dog prior to the search, the validity of such a claim can still come into question. In a U.S. Circuit Court ruling, whose results were shared by the American Society of Canine Trainers, it was established that a drug sniffing dog must officially alert to the potential presence of drugs in order to establish probable cause. Simply showing interest in or casting towards a vehicle is not enough.
Even in situations where the dog does alert, one may still be able to call into question the reliability of such a response as evidence. Further information shared by the ASCT shows that courts have recognized the accuracy of drug dog alerts to be as low as 62 percent.